N, S = map(int, input().split())

fact = [1] * (S + 1)
for i in range(1, S + 1):
    fact[i] = i * fact[i - 1]

perm = [0] * S
nums = list(range(1, S + 1))
for i in range(S):
    j = N // fact[S - i - 1]
    N -= fact[S - i - 1] * j
    perm[i] = nums[j]
    nums = nums[:j] + nums[j + 1:]
inv = [0] * S
for i in range(S):
    inv[perm[i] - 1] = i + 1
ans = 0
nums = list(range(1, S + 1))
for i in range(S):
    j = nums.index(inv[i])
    ans += j * fact[S - i - 1]
    nums = nums[:j] + nums[j + 1:]
print(ans)